1. Field
This application relates to communication networks and, more particularly, to a method and apparatus for collecting management information on a communication network.
2. Description of the Related Art
Data communication networks may include various computers, servers, nodes, routers, switches, hubs, proxies, and other devices coupled to and configured to pass data to one another. These devices will be referred to herein as “network elements,” and may provide a variety of network resources on the communication network. Conventionally, data has been communicated through the data communication networks by passing protocol data units (or cells, frames, or segments) over links extending between the network devices. A particular protocol data unit may be handled by multiple network devices and cross multiple communication links as it travels between its source and its destination over the network.
Network elements operating on the network may monitor numerous aspects of their status, flows passing through the network, and operation of the network itself. Indeed, a conventional network element may be configured to monitor over a thousand different aspects of its operation. Management information of this nature is conventionally stored in a Management Information Base (MIB) although it may be stored elsewhere on the network element as well. Information from the MIB is then conveyed to a management station to enable a network operator to monitor the health of the network and network elements operating on the network.
Transmission of the thousands or more of aspects of network performance and health from the network elements to the management station has several drawbacks. First, as the number of monitored attributes on the network elements increases and as the number of network elements on the communication network increases, the amount of overhead attributable to network management increases, thus limiting scalability of the network. Second, a management station on the network is typically charged with monitoring the performance and health of a number of network elements. As the size of the network elements, and hence the amount of management information increases, and as the number of managed network elements increases, the volume of information that must be collected and processed increases, which also impacts the scalability of the network. Finally, the network elements on a network may be manufactured by numerous companies which may be configured to generate different management information. Accordingly, in addition to increasing the complexity of the management station software which is tasked with interpreting the data received from the managed elements, detailed knowledge of the underlying technology is required to extract meaningful information from the collected management information.
Attempts have been made to reduce the overhead on the network and also to reduce the complexity of the management information. For example, applications have been created to remotely monitor managed entities and cache the results of the queries and make the results available to the management application or operator. This method still requires the transmission of large amounts of information on the network and has an additional problem that the information in the cache may become stale.
Another method that has been attempted is to create specialized queries on the network elements that monitor specific key measurements for an undesirable behavior. While this may alleviate the need to transport all of the management information on the network, it requires specialized knowledge of the specific technologies and encounters scalability problems with large devices or on large networks. Additionally, attempts have been made to define technology neutral health indicators, but these are not universally available. Where the health indicators are computed by the network element, the raw data supporting the health indicator is not transferred on the network, thus reducing the amount of traffic on the network, but it is not always clear how these health indicators relate to the technology specific measurements underlying the health indicator. It can therefore be difficult to determine what information to retrieve from the network element to ascertain additional information about the state of the network element when a health indicator indicates an unhealthy condition. Additionally, where the health indicators are computed by the management station, the raw information is required to be transmitted on the network which, as indicated above, is undesirable for several reasons.